Speaker
Description
Weyl semimetal is a topological nontrivial phase of condensed matter which hosts 2-fold degenerate Weyl nodes formed by unavoidable crossings of linearly dispersive bands. The tilted Weyl cone, Lorentz invariance violation and unusual transport properties distinguish the type-II WSM from its type-I counterpart. By combining ARPES study and first-principles calculations, we present the observation of Weyl nodes in type-II WSM WP2. Different from other type-II WSM, the Weyl nodes with opposite chirality origin from 4-fold degenerate points, which ensure they are robust to external interferences, and which is likely the reason for the novel transport properties in WP2. Most important, our study shows the first observation of 4-fold degenerate points splitting.